In industry and in many applications it is needed to combine streams, solutions, slurries together either to use them as a combined reaction medium or as a finished product. Usually one is confronted with a dilution effect or one has to apply drying methods, which can be ineffective, and/or expensive.
It is know to employ hydrocyclones in the treatment of particular feedstock for the purpose of removing impurities or relatively low grade substances, such as contaminants. Such contaminants may for example be present in solution in a liquid medium in which the particulate feedstock is suspended, and/or they may be present as undissolved solid particles.
According to one commonly used procedure, use is made of a plurality of hydrocyclone stages arranged in series or cascade for performing a continuous countercurrent washing process. The particulate feedstock together with the liquid medium, which contains dissolved contaminants, is fed into the first hydrocyclone stage and fresh liquid is continuously fed into the last stage. U.S. Pat. No. 4,283,232 discuss such a typical set-up of hydrocyclones.
In industry, many reactions are carried out using a heterogeneous mixture of substances such as a suspension of solid or undissolved substances, which are finely distributed in a reaction liquid. Such suspensions are often referred to as slurries or reaction slurries. In these slurries, the reaction liquid does not solubilize the undissolved substances or it solubilizes only a part of these substances so that the remaining part is not dissolved. Frequently some of the reactants, products and/or reaction components that are not converted during the reaction, such as catalysts or other reaction aids which provide a suitable reaction environment and/or promote the reaction are dissolved in the reaction medium, while others are suspended but not or not fully solubilized.
Hydrocyclones are typically used in the treatment of heterogeneous mixtures and examples are for instance in pulp and paper mills to remove sand, staples, plastic particles and other contaminants, in the drilling industry to separate sand from the expensive clay that is used for lubrication during the drilling, in industry to separate oil from water or vice versa, and in metal working to separate metal particles from cooling liquid.
U.S. Pat. No. 3,890,888 also describes a hydrocyclone-based apparatus for the recovery of non-diluted or little diluted juice and of starch from root crops.
GB 2 011 451 describes a process and apparatus for the production of modified starches wherein a starch slurry is centrifuged and the resulting cake is then diluted and submitted to chemical modification, modified starch slurry is then centrifuged and the filtrate is recycled back to the dilution tank whereby it is used to dilute reactants thus avoiding elimination of waste waters.
Hence, there is still a need in the art for a process of effectively utilizing hydrocyclones, disk, or nozzle centrifuges for preparing a slurry.